Give something a grey / white chequerboard background, in two lines of CSS. Stolen from somewhere on Stack Overflow IIRC.

chequerboard.css

.my-element {
	background-image: conic-gradient(#ddd 25%, #fff 25%, #fff 50%, #ddd 50%, #ddd 75%, #fff 75%);
	background-size: 40px 40px;
}